Use a global Config struct for arguments & accept log file as an argument

[AJ-Williams1]

Problem

Firmware currently accepts command-line arguments for controlling policy-scale, kp-scale, and kd-scale. These arguments are parsed in robot_description.rs, rather than early on in main. This makes it difficult to add new arguments which affect other parts of the code--in this case an argument to specify where log files should be saved.

Solution

Arguments are now parsed first thing, in main, and placed into a Config struct. This struct is then passed through a series of functions to RobotDescription. I've also added an argument for the log file.

[gitfish7]

Looks good, do we have build + run validation to ensure no regressions?

[gitfish7]

Changes look good, let's fix the commit messages and post some validation! Will approve after

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